1. Field of the Invention
This invention relates to an impact tool of simple yet highly effective construction which has numerous advantages including easy portability, compactness, and the ability to be used in extremely detailed, precise and fine engraving, carving, and stone setting work. More particularly, it is concerned with an impact tool having a hand-held impact device having a cylindrical, hollow body and a piston received within the body for delivering impact energy to the device, conduit for directing and venting motive fluid to and from the hand-held impact device for shifting of the piston therein, and a valve especially adapted for operably coupling the directing and venting conduit to the hand-held device in alternative fashion at a variable, rapid rate.
2. Description of the Prior Art
Power impact tools for engraving, carving or cutting metals, wood, stone and the like are well known in the art. U.S. Pat. No. 3,393,755, for instance, for which I was co-inventor, discloses such an impact too. Previous impact tools, however, have been somewhat limited in applications involving highly delicate, precision engraving work or stone setting due to a relatively limited range in power and stroke speed range. Highly delicate work requires an impact tool that delivers a low impact energy level for each stroke of the tool and that is capable of delivering such low impact strokes at a rapid rate. Moreover, previous hand-held impact tools have required a specialized source of pressurized motive fluid that alternatively provided a positive pressure and a vacuum to the hand-held impact device.